1. Field of Invention
The field of the currently claimed embodiments of this invention relates to systems and methods for planning patient-specific cardiac procedures.
2. Discussion of Related Art
Ventricular tachyarrhythmia (VT) frequently occurs in the setting of myocardial infarction (MI). Catheter-based ablation is a promising procedure which has become first-line therapy for many types of cardiac arrhythmias (E. Delacretaz, W. G. Stevenson, Catheter ablation of ventricular tachycardia in patients with coronary heart disease: part I: Mapping. Pacing Clin. Electrophysiol. 24, 1261-1277 (2001); K. Soejima, M. Suzuki, W. H. Maisel, C. B. Brunckhorst, E. Delacretaz, L. Blier, S. Tung, H. Khan, W. G. Stevenson, Catheter ablation in patients with multiple and unstable ventricular tachycardias after myocardial infarction: short ablation lines guided by reentry circuit isthmuses and sinus rhythm mapping. Circulation. 104, 664-669 (2001)). However, catheter ablation has achieved low levels of success in eliminating MI-related VT; only 58% initial success rate and 71% eventual success rate following repeated procedures, with complications rate as high as 8% of the treated population (D. J. Callans, E. Zado, B. H. Sarter, D. Schwartzman, C. D. Gottlieb, F. E. Marchlinski, Efficacy of radiofrequency catheter ablation for ventricular tachycardia in healed myocardial infarction. Am. J. Cardiol. 82, 429-432 (1998)).
The low efficacy of catheter ablation for infarct-related VT stems from the fact that current voltage and pace mapping techniques to identify the targets of ablation are associated with numerous limitations, including ambiguities in correlating maps with anatomy (J. Dong, D. Dalal, D. Scherr, A. Cheema, S. Nazarian, K. Bilchick, I. Almasry, A. Cheng, C. A. Henrikson, D. Spragg, J. E. Marine, R. D. Berger, H. Calkins, Impact of heart rhythm status on registration accuracy of the left atrium for catheter ablation of atrial fibrillation. J. Cardiovasc. Electrophysiol. 18, 1269-1276 (2007)), and insufficient resolution in identifying ablation targets, resulting from the point-by-point sampling nature of current mapping techniques (J. Brugada, A. Berruezo, A. Cuesta, J. Osca, E. Chueca, X. Fosch, L. Wayar, L. Mont, Nonsurgical transthoracic epicardial radiofrequency ablation: an alternative in incessant ventricular tachycardia. J. Am. Coll. Cardiol. 41, 2036-2043 (2003); E. Sosa, M. Scanavacca, A. d'Avila, F. Oliveira, J. A. Ramires, Nonsurgical transthoracic epicardial catheter ablation to treat recurrent ventricular tachycardia occurring late after myocardial infarction. J. Am. Coll. Cardiol. 35, 1442-1449 (2000); H. Zhong, J. M. Lacomis, D. Schwartzman, On the accuracy of CartoMerge for guiding posterior left atrial ablation in man Heart Rhythm. 4, 595-602 (2007)). Furthermore, the complex 3D pathways along which the cardiac impulse propagates around/through the zone of infarct during VT, are difficult to reconstruct on the basis of electrical interrogation of ventricular surfaces only (J. M. de Bakker, F. J. van Capelle, M. J. Janse, A. A. Wilde, R. Coronel, A. E. Becker, K. P. Dingemans, N. M. van Hemel, R. N. Hauer, Reentry as a cause of ventricular tachycardia in patients with chronic ischemic heart disease: electrophysiologic and anatomic correlation. Circulation. 77, 589-606 (1988); N. Peters, A. Wit, Myocardial architecture and ventricular arrhythmogenesis. Circulation. 97, 1746-1754 (1998)). These limitations prolong procedure duration, greatly increasing the risk of chamber perforation, thromboemboli, and radiation overexposure, and limit the success of the therapy.
New approaches that deliver swift and accurate identification of optimal infarct-related VT ablation targets will dramatically improve the efficacy of the therapy and increase its tolerance while reducing post-procedure complications. This will result in a dramatic medical and economic impact on both the lives of patients and the society at large.
In addition, heart failure is a major cause of morbidity and mortality, contributing significantly to global health expenditure. Heart failure patients often exhibit contractile dyssynchrony, which diminishes cardiac systolic function. Cardiac resynchronization therapy (CRT), a treatment modality that employs bi-ventricular (bi-V) pacing to re-coordinate the contraction of the heart, is a valuable therapeutic option for such patients. CRT has been shown to improve heart failure symptoms and reduce hospitalization, yet approximately 30% of patients fail to respond to the therapy. The poor predictive ability of current approaches to identify potential responders to CRT reflects the incomplete understanding of the complex pathophysiologic and electromechanical factors that need to be considered to achieve optimal resynchronization in each dyssychronous heart.
Therefore, there remains a need for improved systems and methods for planning patient-specific cardiac procedures.